yes, learnin language is very hard, esp when u are yr 7 or above... tis a catastrophe... but i think bein in a environment free of non-english speakin students would be more beneficial to the improvement of the language skills, altho it might not be particularly pleasing, and to certain individuals, may be detrimental on da long run... cuz lyk no one shares a language or even interest wif u... to those hu are conserved, they will be isolated and eventually become lonely etc... for those hu are sociable in da first place, the different environment can only make them grow stronger...
in addition to language, culture change is also very important... lyk, when i got to aust, i didn't share a same culture with the studentz in aust, or even foreign students from other country... ( i went to an IEC u c)... just suggestions... =)